Sprag attachment for wheeled trucks



' 5m, 12, 1932. J. P. GRUNDON 1,340,666

SPRAG ATTACHMENT FOR WHEELED TRUCKS 2 Sheets-Sheet 1 Filed Nov. 11, 1929 Jan. 12, '1932. .1. P. GRUNDON 1,840,666

SPRAG ATTACHMENT FOR WHEELED TRUCKS 2 Sheets-Sheet 2 Filed Nov. 11, 1929 Jzzzrehior c707??? 32 @rzzrzdozz Patented Jan. 12, I932 JOHN P. GRUNDON, FFOR'B-DODGE,"IOWA;

'ASSIGNO-R TO SARGENT MACHINE COMPANY,

031' FORT DODGE, 'IOWA A CORPORATION OF IOWA SIB-RAG rATTACHMENT Application filed November 11 The object of-thisinvention is to provide an improved sprag attachment for wheeled trucks and particularly for truckswhich are wheeled trucks for carrying excavating mechanisms, which attachment is useful, during operation of the excavatingmechanism, for relieving apart of the strain-on the truck wheels'and springs for" keeping the truck wheels from rolling for stabilizing and preventing the tipping of'the' truck and devices carried thereby and for} providing afirm base or anchor against'whichthepull or thrust on the excavatingdevicemaybe exerted. I

More specifically, another objectoftheim vention is to provide an improvedspragj attachment for wheeled -tracks inbluding a transversely arranged shoe havingzuprights pivotally attached to the rear end of the truck Still another object. of the invention is to provide improved means for holding the sprag attachment in inoperative position.

Another and further object is to provide improved means for' adjustingthe heightof the sprag attachment fordi-fl'erent trucks or for different conditions of service. I

With these and other objects in vvi'ewm'y invention conslsts 1n the construction, arrangement and combination of. the various. parts of my device, whereby the objects contemplated are attained, as hereinafter more fully set forth, pointed. out in my claims and illustrated in the accompanying drawings, in which:

Figure l isa perspective View illustrating a portion of a Wheeled truck towhich my improved sprag attachment is applied, theati tachment being shown in operative position.

Figure 2 is an: the same.

Figure 3 is a view similar toFigure; 2;. the solid lines showing the" attachment. in-inope ative: position and the dotted lines i l lu'strat enlarged side elevation of FOR WHEELED TRUCKS 1929. Serial No. 406,491.

ing it in the position assumed immediately prior to placing it in operation.

nigui'e 4 is a transverse vertical section of the truck and attachment, the right hand side igure 5 is an enlarged elevation substantially' on the line 5-5 of Figure 4, illustrating the means for lifting the attachment to inoperative position.

For certain kinds of work and particularly for the purpose of-facilitating transportation, it is desirable to mount excavating devices on wheeled trucks, such as motor trucks having power plants for moving them from p'laceto place: and which may-also be employed for operating the excavating device.

' n: the accompanying drawings I have rying a truck frame 16 which includes spaced I beam sills or side beams.

As here shown, the truck frame supports a platform18 upon which a boom 20 is pivoted' onv the horizontal axis 22. The boom 20 may constitute a part of any suitable type of excavating or hoisting mechanism such as a drag line, clamshell, back filler or crane.

It is obvious that by mounting excavating or hoisting devices on a movable truck, the problem of transporting the machine to variouspla ces is greatly facilitated. However, this type of mounting is not altogether satis factory during operation of the mechanism for the reason that the wheeled truck does not-afford a stable-base or foundation, but is apt to move under stress of the working by rolling of the ground wheels or by tipping of the frame 10 and platform 18 because of being m'ormted'on the truck springs.

My improved sprag attachment is particularly designed for stabilizing the truck frame while the truck is-at' rest andparticularly during operation of the excavating or hoisting device.

l have provided a shoe 24 which may well be-oomp'osed of asection of heavy wooden plank preferably of length corresponding the truck one of the posts.

substantially with the width of the truck. The shoe 24 is arranged transversely at the rear of the rear wheels 10 of the truck and is adapted to rest on the ground surface when in operative position.

A pair of posts are spaced apart on and rise from the shoe 24. These posts may be formed of channel beams 26 attached to the upper surface of the shoe 24 by angle braces 28. The channeled posts preferably are arranged immediately behind the two rear wheels of the truck.

A shaft 30 is journaled in the rear portions of the I beams constituting the frame 16 of and the channeled posts 26 are suitably attached to the shaft. 1

The posts 26 may be attached directly to the ends of the shaft 30, but I prefer to provide means for adjusting the parts at times and for this purpose I have shown arms 32 mounted within the upper ends of the respective posts 26. Each arm is formed with a plurality of spaced apertures 34 to selectively receive a bolt 36 which is extended through Each arm 32 has at its upper end a hub member 38 which receives and is rigidly fixed to the shaft 30. By this means the attachment may be adjusted somewhat as to height, to adapt it for use on different trucks and for different conditions 0 work. i Y

Each post 26 may carry on its forward face a wooden block 40 which tact with one of the truck wheels 10 when the sprag attachment is in position for use.

For practical use the attachment is mounted on the truck in such position that when the posts 26 are in vertical position the Wooden blocks 40 will engage the rear sides of the truck wheels 10. The parts are also adjusted so that when the attachment is in operative position the weight on wheels and springs will be somewhat relieved and will be borne in part bythe sprag attachment. In other words, the distance from the bottom of the shoe 24 to the shaft 30 is slightly greater than the normal height of said shaft above the ground level, so that when the attachment is in position for use, the vehicle springs 14 will be relieved of some of their tension and will not be flattened to their normal extent. This is indicated by the comparative positions of the parts in Figures 2 and 3.

Means is provided for lifting and holding the sprag attachment in inoperative position at times, particularly during traveling of the truck. This means may be of any desired construction, but I have here shown a stub shaft 42 journaled in the rear end of the truck frame 16. The stub shaft 42 carries at one end a hand crank 44 and atthe other end a drum 46. A cable 48is attached at one end to the drum 46 and is adapted to be wound thereon by f rear wheels 10 which thus is designed to con-.

the truckrotation of the shaft.

42 in one direction. The opposite end of the cable 48 is attached to the sprag device as by means of a clip 50 carried by the rear side of one of the posts 26.

The stub shaft 42 is provided with a ratchet wheel 52 and a pawl 54 is pivotally mounted for engagement with said ratchet for holding the shaft and drum 46 against reverse rotation and thereby maintaining the sprag attachment in inoperative position as shown in Figure 3 \Vhen it is desired to use the sprag attachment, the pawl 54 is lifted manually and the device then drops to the posit-ion indicated by dotted lines in Figure 3. It will be noted that the device thus assumes an inclined position extending rearwardly and downwardly from the truck frame, with the forward margin of the shoe 24 resting on the round.

The truck is then backed a short distance, causing the sprag attachment to assume a vertical position and the truck frame rides up onto and is partially supported by the attachment.

It will be noted that the sprag attachment is of sufficient height that it does not entirely assume the weight of the rear end of the truck and that some weight remains on the have a tractive contact with the ground surface. It follows that the weight of the truck can be easily and quickly removed from the sprag attachment by simply moving the truck in a forward direction.

When the sprag attachment is in its operative position as shown in Figure 2, it serves as a rigid support to prevent rearward rolling of the truck wheels 10 and that it also prevents lateral tipping of the truck frame and excavating devices by unequal yielding of vehicle springs 14. In other words, the sprag attachment stabilizes the support for the excavating or hoisting mechanism and serves to hold its support in the desired position for operation of the mechanism.

The attachment also serves the function of providing a rigid base or anchor against which pull or thrust of the excavating or hoisting device maybe exerted. This function arises particularly in those cases where the boom 20 supports a drag line excavator in which there is a pull of the drag line toward the truck.

This sprag attachment greatly facilitates the operation of excavating and hoisting devices when mounted upon a movable truck.

It is obvious that various changes may made in the form, sizes, rangement of the parts, within the scope of the appended claims, without departing from my invention.

' I claim as my invention:

1. A sprag attachment for wheeled trucks comprising spaced standards pivoted to the materials and artruck frame, and a shoe carried by the lower ends of said standards, arranged transversely adjacent a pair of ground Wheels of the truck, said shoe adapted to contact with the ground surface when said standards are in upright position, for assuming a portion only 0 the Weight of the truck and its load, and buffer blocks carried by said standards for engaging the near-by ground Wheels of the truck.

2. A sprag attachment for wheeled trucks comprising spaced standards pivoted to the truck frame, ground engaging means on the lower ends of said standards for contacting the ground surface when the standards are in upright position, and buffer blocks carried by said standards for engaging adjacent ground Wheels of the truck.

Des Moines, Iowa, September 3, 1929.

JOHN P. GRUNDON. 

